After updating I went to my prefs.js to change a few things. Then I could see that several sites were whitelisted in my AdBlock Plus which i never have whitelisted. I have not been reading much about Adblock Plus, but maybe someone here can fill me in. I uninstalled the thing, and then had to remove it's tracks in the prefs.js since the still were there. Has anyone any knowledge about this whitelisting issue? I am very sure I did not whitelist those sites in there.

There are improvements to tabs as well: Firefox now opens with a second tab active and you can 'tear off' tabs into their own separate windows. Speed is an increasingly hot topic, and 3.5 performs well in benchmark tests against previous versions. In our tests, it was nearly four times as fast as IE8 using the SunSpider JavaScript benchmark. The real progress is for developers.